The Electron launch vehicle first stage has nine Rutherford engines In addition to adapting the single-engine-out-friendly nine engine configuration from the Falcon-9, the rocket carries a significant mass of batteries in order to power two electric motor-driven propellant pumps for fuel and oxidizer.
For a given amount of work (Joules) the lower energy density (Joules per kilogram) of electrical batteries means they are something like 50 times heavier than the LOX/RP-1 needed to do the same work.
The tradeoff is simplicity versus newness of technology and battery mass. Newness did not seem to be a problem (highly reliable electric motor driven pumps in hostile environments are a mature technology on Earth) and the battery mass can be at least party offset by dropping spent batteries ("battery staging").
Question: Does electric fuel pumping scale well for rockets? Is the Electron at a "sweet spot" in terms of size, or would smaller and (much) larger rockets see similar tradeoffs (qualitatively and quantitatively) if going the electric fuel pump route?
- What is the mass of the Electron rocket's battery pack? (currently unanswered)
- What was ejected from RocketLab's Electron launch vehicle at T+6:25 during stage two burn?
- Are the ejected first stage Electron rocket batteries really incinerated? (currently unanswered)
- What are the two very large "blue" cylinders attaching to the combustion chamber of each Rutherford Engine?
- Do rocket labs store propellants at higher pressure than the other rockets? (currently unanswered)
- Are LiPo batteries more suitable for 1st stage electric power than Li-ion batteries? (currently unanswered)
- Rocket flywheel instead of battery/generator (crazy idea)?